Subjects
In 1979 the Peruvian Primatological Project "Manuel Moro Sommo" (PPP) initiated studies on the adaptation and reproduction in captivity of A. nancymai (2n = 54 chromosomes) at the CRCP (73' W, 4' S). Animals were collected from the management areas of the PPP in the Peruvian Amazonia [Aquino & Incarnation, 1988].
Housing and Social Groups
In February, 1979, seven wildcaught adult female owl monkeys were housed as pairs with wildcaught adult males. Additional breeding pairs were added during the year and subsequent years according to availability of animals (Table 1). The offspring remained with their parents after a subsequent birth so that the first offspring was able to observe or "learn" the parental reproductive behavior and neonatal care. If a new infant was not produced within 1.52 years, the juvenile was removed. These family groups were kept in cages of 1 X 1 X 2 m (1 X w X h), furnished with two branches and a nest box (40 x 30 x 30 cm).
Light Cycle
The owl monkeys were maintained under natural photoperiod conditions with approximately 13 hours of light each day, length varying with seasonality.
Temperature and Humidity
The cages were kept in a building with wide wire mesh windows. The mean temperature throughout the year was 26ºC (24.128.1ºC) and the annual mean precipitation 3,115 mm (2,4833,359 mm). The rainy season begins in November and extends through April.
Diet
,The animals were fed once a day with 3035 g of a biscuit (21% crude protein) prepared at the CRCP and 3540 g of fruit (banana or apple) per animal, given at 16:30 hours. Water was available at all times.
Data Collection
Ten years of reproductive records of the CRCP were examined to obtain data on litter size, sex ratio, seasonality of births, age at first birth, and reproductive success.
